There are various apparatuses equipped with an ion generation device which utilizes a discharge phenomenon, and they are used in various environments. At present, discharge devices having a structure that a substrate to which a discharge electrode is fixed or a discharge electrode itself is fixed to a structural body such as resin and the periphery thereof is covered with an insulator are under development.
Currently, a metal needle is mainly adopted as an electrode used for the discharge phenomenon, and discharge electrodes made of SUS, tungsten, a nickel alloy, or the like are put to practical use. The surface of at least a body portion of a discharge electrode is plated with tin, nickel, or the like in order to solder the discharge electrode to a substrate. Corona discharge is generated at a tip of a metal needle to generate ions.
According to a device described in Japanese Patent Laying-Open No. 2010-77462 (PTD 1), a discharge electrode is made of a simple substance or an alloy of a transition metal such as gold, silver, or titanium, or a member plated with a transition metal, and particles of the transition metal are emitted to the outside to obtain an antibacterial effect.
Japanese Patent Laying-Open No. 2007-27074 (PTD 2) discloses a discharge electrode needle in which a needle-like electrode formed by plating a metal with gold is used to improve generation of corona discharge more effectively even at a low voltage, and thus negative ions and ozone can be generated in larger quantities.